1. Field of the Invention
The present invention relates to a method for manufacturing an inter-layer insulating film applied to a semiconductor device and, more particularly, to a method for reducing the effect of an under-layer substrate on which a silicon dioxide (SiO.sub.2) inter-layer film is formed with a chemical vapor deposition (CVD) using as source gases an ozone (O.sub.3) and a tetraethoxy-silane(TEOS).
2. Related Arts
A high density integration technology has been remarkably developed particularly in semiconductor devices. A stacked layer structure has been widely employed in semiconductor devices to accomplish the high density integration in a restricted area. These semiconductor devices require flatness on the surface of the inter-layer insulating film because, if the surface is formed roughly, it becomes difficult for subsequent manufacturing steps to process the inter-layer film and its upper layer film, which causes a reduced yield of semiconductor devices.
A NSG (Non-doped Silicate Glass) film, which is manufactured by CVD utilizing the reaction of TEOS, has recently been used as an inter-layer insulating film revealing excellent flatness.
However, the growth of O.sub.3 -TEOS NSG film is highly influenced depending on the under-layer film. Some of the under-layer films create abnormally grown O.sub.3 -TEOS NSG film thereon, which may reveal roughness of the surface, losing inherent quality of flatness of O.sub.3 -TEOS NSG film.